Cinematograph and safety device therefor



APPLICATION FILED MAR I7, 1920.

Patented June 7, 1921.

2 HE gs suan I. W)

W. VAN DEN BROECK.

CINEMATOGRAPH AND SAFETY DEVICE THEREFOR.

APPLICATION I 'ILED MAR- 17, I920.

Patented June 7, 1921.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE- CINEMATQGRAPH AND SAFETY DEVICE THEREFOR.

Specification of Letters Patent.

Patented June '7, 1921.

Application filed March 17, 1920. Serial No. 366,636.

To all whom. it may concern:

Be it known that I, WILLIAM 'VAN DEN BRoEoK, a subject of the King ofthe Belgians,.residing at London, England, have invented certain new anduseful Improvements in Cinematographs and Safety. Devices Therefor, ofwhich the following is a specification.

This invention consists in improvements in or relating to cinematographsand safety devices therefor, theobject being to prevent fire and avoiddestruction of films.

Specific objects are to provide means for shutting off the film from thelantern immediately a break occurs in the film passing the gate; meansfor stopping the film feed immediately such a break occurs; means forprotecting from fire the film approaching the gate; and means forshutting off the film from the lantern when the speed of the drivingmechanism falls below a predetermined minimum.

A cinematograph according to this invention, comprises, a spring closedsliding door incorporated in a frame attached to the gate between thesource of light and the film; a detent to hold the door open while thefilm is intact; a system of spring actuated levers or the like,dependent for their position upon the continuity of the film in the gateand arranged so as to release the detent when the film breaks.

A further feature of the invention lies in the employment of the actionof the closing door, as a means for automatically cutting out the drivefor the film feed. This is accomplished by a system of levers,hereinafter described, actuated by the closing door, and so arranged asto withdrawa pin supporting a gravity-arm lever. This arm is so designedthat on falling 1t separates the two worm wheels which constitute thedrive of the film feed.

e A further feature of this invention is the provision of a boxdisposedon the feed side (say top) of the gate and so arranged that whena break ofthe film occurs in the the employment of a second slidingdoor, in

the frame attached to the gate, operatively connected with a governor orequivalent in gravitythe driving mechanism, so that the said door isautomatically closed when'the speed of the feed mechanism falls below adetermined figure, and is automatically opened when the normal speed isagain established.

For a more complete understanding of the invention there will now bedescribed a cinematograph projector incorporating types of constructionfor the improvements enumerated above.

It is to be understood that this description is given by the way ofexample only and the constructional details enumerated may be modifiedin many respects without departing from the spirit and scopeof theinvention.

In the accompanying drawing Figure 1 is a perspective view of thelantern side of the projector. I

Fig. 2 is an elevation of thespring closed door and the plate on whichit slides, showing the position of the door and controlling mechanismwhen the door is closed.

Fig. 3 the same as Fig. 2, showing the position of the door andcontrolling mechanism when the door is open.

Fig. 4 is a section through the frame and g e Fig. 5 is a perspectivedetail of a form of construction suitable for withdrawing the support ofthe gravity arm.

Like letters of reference indicate like parts throughout the drawings.

The constructionof the spring-closed door and the mechanism foroperating the same will first be described.

The door 1 comprising a sheet of material in which two slots '2 are cut,one being located along the top and the other along the bottom, slidesupon four pins 3 or the ls ke located in said slots and fixed in a plate6 which is incorporated in a detachable frame 52. This frame is attachedto the back (lantern side) of the gate 18. A convenient projection 4 isformed on one extremity of the door so that it may he slid open by handwhen required. The door is opened against the action of two springs 5.The door, when open is kept in position by a detent lever 7, which ispivoted on a pin 8 or the like fixed in the plate 6. One end of thislever is formed so that it may be pressed down by hand and the other endis formed to hook over the corner ofthe door and also to rest on theextremity of a further lever 9. The detent lever is kept in pos1- 'awedge shaped projection 13.

of the main frame.

tion when the door is open by being pressed by the action of a spring 11against a stop 10 fixed to the framework. The lever 9 is approximatelyU-shaped and is pivoted at the bottom of the U upon a pin 12 or the likefixed to the plate 6. One extremity of this lever bears against thedetent lever as described and the other has formed upon it Bearing uponthis projection is the extremity of a further lever 14, the plane ofrotation of which is at right angles to that of the aforesaid levers andparallel to the direction of motion of the film 53. This lever ispivoted on a pin 15 or the like which'is fixed to an angle member 16attached to the plate 6. One end of this lever bears on the wedgeportion 13 as described. The other end is bent inward toward the gateand rests upon v the edge of the film 53 and is'kept pressed up againstit by means ofythe spring 17.

The working of this mechanism is then as follows. After having threadedup the film in the usual manner, the door 1 is slid open by hand againstthe action of the spring 5,

'until the detentlever 7 springs into place.

The detent lever is not disturbed by levers 9 and 14 since the motion ofthe latter is restrained by the film. Having started the cinematographshould a break occur in the film while it is passing the gate, the endof lever 14 which is normally pressed against the film will immediatelymove forward, the

other end will press against the wedge portion of lever 9 causing thewhole to rotate and thereby to lift the detent which in its turnreleases the door. The door will then be closed under the action ofsprings 5.

. The mechanism by means of which the spring closed door causes the filmfeed to be stopped will next be described.

' A horizontal pin 19 is mounted in guides 20 which are fixed to theplate 6. The

whole is so situated that the door upon closing "bears against one endof the said pin causing it to slide in its bearings against the actionof a spring 21. The other extremity of the pin bears against a radialabutment 22 mounted on a vertical rotatable spring controlled spindle23. This spindleis supported in bearings 24 which are fixed to thestandard of the machine. Mounted on the upper end of this spindle is atoggle lever 25 against which rests the spindle con trol spring 26.Pivoted to the end of the toggle lever is apawl 27. The rotation of thespindle causes an endwise motion to the pawhsince it is preventedrotating with the toggle lever by bearing against a part The end face ofthe pawl is formed at an angle to the direction of endwise motion.

A lever 28, with a vertical pivot 29 parallel tospindle 23, is arrangedso that one extremity bears upon the end face of said the film feed, thesprocket wheel 34 ismounted above the gate in the standard of themachine, on the rotatable shaft 35. Mounted on this shaft is a slidingsleeve 36 which may be keyedor otherwise non-ro tatably engaged with theshaft. "This sleeve carries a wormwheel 37 and in one position of thesleeve (the operative position) the worm wheel is engaged by, a worm 38,but in another position of the sleeve the worm wheel is out ofengagement with the worm, so that the'sprocket wheel is not then driven.The slidingsleeve is preferably actuated by a gravity bell crank lever39 pivotally mounted in the standard. The connection between the sleeveand said lever is formed by a pin 40 fixed to the sleeve and arrangedoperative position, the bell crank lever is supported by the pin 31already described.

The com lete action then of the mechanism is as ollows: The door 1 uponclosing, forces the pin 19 against the radial abutment 22' causing thespindle 23 and toggle lever 25 to'rotate. The rotation of the togglelever produces endwise motion in the. pawl 27, theend faceof whichpressing against the leverv 28 causes the latter to rotate and therebyto withdraw the pin 31. The effect of the withdrawal of The apparatusconsists of a box 42 such as shown dotted in Fig. 1 which is attached Ibetween the feed sprocket wheel 34 and the film side of the gate. Thisbox serves two purposes,'firstly to collectany film fed in by thesprocket after the film has broken, secondly in normal circumstances toprotect to the gate or in the case where a break has occurred to protectthe film fed into the box... The box is. clamped "to the gate bysuitable clamps as. The mechanismnext described; is a means for closinga second sliding door in the frame, when a predetermined mint from firethe film passing from the sprocket mum speed is reached and for openingthe same when the normal speed is again established. A governor 55, suchas shown in Fig. 1, is incorporated in one of the rotating parts of themachines and is connected through levers 4A, 45 and 46 and links 47 and48 to the sliding door 49. The said 'door is preferably made fromasbestos. The slide for this door is formed in the plate 50 which isattached to plate 6. To the lan tern side of plate 50 is attached anasbestos sheet 51.

It will be appreciated that the framework carrying the sliding doorsforms a readily attachable unit which can be afiixed without difiicultyto existing cinematographs by means of two or more screws 54.

In a cinematograph the film, should it rupture,

to be fed by the mechanism above the gate. This is a frequent cause offires inasmuch as the film passing the gate, although it is providedwith pads above and below which prevent the, spread of fire along thefilm, causes a puff of flame backward toward the condenser. The film,approaching the gate from above, very rapidly forms a slack loop whichhangs down between the condenser and the gate and meets the puff offlame and becomes ignited. The sliding-door mechanism above described,by closing the instant that the film is ruptured either by ignition orotherwise, prevents the puff of fiame from coming out, and thus acts ofitself to prevent fires. As an additional safeguard, however, there ispreferably provided, above the gate frame, an approximately semicircularbox through which the film,-in being fed downward, passes. On rupturethe film, instead of forming a slack loop hanging down between thecondenser and the gate,

and the operator hasc'ollects into the box, time to stop the machinewithout a fire commencing. As the machine slows down the asbestoscovered sliding-door moves over and cuts off the heat from the gateframe.

The expression gate frame employed in the following claims is intendedto cover that portion of a cinematographprojector which surroundsandsupports the film in the immediate neighborhood of the projectionopening.

What I claim as my invention and desire Letters Patent is to secure by 7device for a cinematograph 1. In a safety having a light source, gateframe, a film therein, a sliding door in the said frame between thelight source and the film, self acting means within said frame forclosing the door when free, means within said frame in contact with andoperated by said film when intact to hold the door open, and meanswithin said frame for releasing the door when said film breaks.

said detent having a light ceases to be drawn through by the a feedmechanism below the gate butcontinues said detent to. release mechanismfor feeding the combinatlon of a acting means film, self-acting meanswithin said frame forclosing the door when free, a detent mounted insaid frame controlled through contact with said film when intact and ar-4 ranged to engage and hold-"the door open, and means within said framefor releasing when the film breaks.

3. Ina safety device for a cinematograph source, the combination of afilm therein, a spring-closed frame between. the light a detent mountedin gate frame, a sliding door in said source and the film, said frameand with said film while intact holding said door open, and means withinsaid frame for releasing said detent when the film breaks.

4. In. a safety device for a cinematograph having alight source, thecombination of a gate frame, a film therein, sliding door in said framebetween the light source and the film, a spring-controlled detentmounted insaid frame arranged to engage and hold the trolled bell-cranklever mounted in said frame engaging with the film at the gate whileintact, an operative .connection at one end between said bell-cranklever and the film breaks.

5. In a safety d the combination of a. gate frame, a film therein, asliding door in the said frame, self-acting means forclosing the doorwhen free, means operated by said film when intact to hold the dooropen, and means forreleasing the door when said film breaks, mechanismfor feeding the film to said gate frame, separable driving gear elementsin said mechanism and means actuatedby the closing of said sliding doorfor separating said elements when the film breaks.

6. In a safety device for a cinematograph, the combination of a gate'frame, a film therein, a sliding self-acting means for closing the doorwhen free, means operated by said film when in-. tact to hold thedooropen, and means controlled through contact a spring-closed doopopen, a spr ng-conthe detent when the vice for a cinematograph door inthe said frame, 1

for

releasing thedoor when said film breaks, Y

said, elements when the film breaks, and

and guarding from" means for collecting. fire the film approaching saidgate.

7 In a safety device for a cinematograph, the combination of a gateframe, in, a sliding door in for closing means operated by said hold thedoor open, means for releasing the the door when free,

the film to said gate a film. therethe said frame, selffilm when intactto door when said film breaks, mechanism for feeding the film to saidgate frame, separable driving gear-elements in said mechanism, meansactuated by the closing of said sliding door for separating saidelements wnen the film breaks, means for collecting and guarding fromfire the film approach ing said gate, a second sliding door in saidframe, a governor in the driving mechanism, and means controlled by saidgovernor for opening and closing said door at predetermined speeds offilm feed.

8. In a safety device for a cinematograph havinga source of light, thecombination of a gate frame, a film therein, a spring controlled doorsliding within said frame between the light source and the said film,said door tending to close, a detent mounted in said frame to hold saiddoor open against said springs, a trip mounted in said frame andnormally in contact with the film and actuated by the breaking of saidfilm to release said detent.

9. In a safety device for a cinematograph having a source of light, thecombination of a gate frame, a film therein, a spring controlled doorsliding within said frame between the light source and the-film, saiddoor tending to close, a detent mounted in said frame to normally holdsaid door open against saidsprings, a pivoted lever mounted in saidframe and bearing against said detent, a spring controlled pivotedbellcrank lever in said frame, bearing at one end against said firstlever and at the other end against said film and so arranged that itsmotion caused by the film breaking releases said detent.

10. In a safety device for a cinematograph, the combination of a gateframe, a film therein, a spring controlled slidin door tending to close,a detent to hold said door open against said springs, a pivoted leverbearin against said detent, a spring controlled pivoted bell-cranklever, bearing as to one end against said first lever and as to theother end against said film and arranged so that its motion caused bythe film breaking releases said detent, a film feed sprocket wheel, ashaft for same, a keyed sliding pinion mounted on said shaft, adrivingpinion with which said sliding pinion in one position engages, apivoted gravity bell-crank lever operatively connected to said slidingplnion, a withdrawable support for said bell-crank lever, a linkwork setin motion by the closing of said door and operatively connected toWithdraw said support.

11. In a safety device fora cinematograph, the combination of a gateframe, a film therein,aspring controlled sliding door tending to close,a detent to hold said door open against said springs, a pivoted leverbearing against said detent, a spring controlled pivoted bell-cranklever, bearing as to one end against said first lever and as to theother end against said film and arrangedso that its motion caused by thefilm breaking releases said detent, a film feed sprocket wheel, a shaftfor same, a keyed sliding pinion mounted on said shaft, a driving pinionwith which said sliding pinion in one position engages, a pivotedgravity bell-crank lever operatively connected to said sliding pinion, awithdrawable support for said bell-crank lever, a linkwork set in motionby the closing of said door and operatively connected to withdraw saidsupport, a box disposed between said film feed sprocket wheel and saidgate frame, to collect and guard from fire said film approaching saidgate frame.

12. In a safety device for a cinematograph, the combination of a gateframe, a film therein,aspring controlled sliding door tending to close,a detent to hold said door open against said springs, a pivoted leverbearing against said detent, a spring controlled pivoted bell-cranklever bearing as to one end against said first lever and as to the otherend against said film and arranged so that its motion caused by the filmbreaking releases said detent, a film feed sprocket wheel, a shaft forsame, a keyed sliding pinion mounted on said shaft, a driving pinionwith which said sliding pinion in one position engages, a pivotedgravity bell-ctrank-lever operatively c nnected? to said sliding pinion,a withdrawable support for said bell-crank lever, a linkwork set inmotion by the closing of said door and operatively connected to withdrawsaid support, a box disposed between said film feed sprocket wheel andsaid gate frame, to collect and guard from fire said film approachingsaid gate frame, a governor in the drlving mechanlsm, a secondslidingdoor in said frame, a linkwork connecting said governor and saidsliding door, so as to close and open it at predetermined speeds.

In testimony whereof I aifix my signature.

W. VAN DEN BROECK.

